Known dry-cleaning processes consist of a wash, rinse, and draining/drying cycle with solvent recovery. During the dry-cleaning process, items, such as garments, are loaded into a basket disposed within a vessel and immersed in a dry-cleaning solvent that is pumped into the vessel from a base tank. Conventional dry-cleaning solvents include perchloroethylene (PCE), petroleum-based or Stoddard solvents, CFC-113, and 1,1,1-trichloroethane, all of which are generally aided by a detergent. Additionally, U.S. Pat. No. 5,467,492, entitled "Dry-Cleaning Garments Using Liquid Carbon Dioxide Under Agitation As Cleaning Medium" discloses an apparatus and method for employing a liquified gas, such as carbon dioxide, as the dry-cleaning solvent.
The dry-cleaning solvent functions to dissolve the soluble soils on the item. The insoluble soils, however, must be physically dislodged from the item. Accordingly, to remove the insoluble soils from the item, the item is typically agitated within the dry-cleaning solvent during the wash and rinse cycles of the dry-cleaning process.
Currently utilized methods for agitating items during dry-cleaning for the purpose of removing insoluble soils have disadvantages. For example, these methods do not provide a means whereby the degree of agitation may be easily controlled. As such, different dry-cleaning machines frequently must be manufactured, purchased, and/or used for items of differing fragility.
Furthermore, in dry-cleaning systems that utilize liquified gas, such as carbon dioxide, as the cleaning solvent, it is necessary that the liquified gas be completely removed from the cleaned items, vaporized to separate the contaminants and foreign particulate matter, and re-liquified for re-circulation through the system. The cycle time for such processing can be lengthy, thereby increasing the operating cost.
Accordingly, a need exists for an improved dry-cleaning system, and in particular, an improved liquified gas dry-cleaning system.